1. Field of the Invention
The invention relates to a compressor having an axially divided casing, comprising a plurality of casing halves, in which the guide vanes are fastened by their roots in peripheral grooves.
2. Discussion of Background
Compressors of this type are known. Usually there are intermediate pieces arranged between the guide vane roots. During running of the compressor, the air is heated by the compression. The compressed air delivers heat to the intermediate pieces and the vane material, which causes these to expand. In order to prevent the stresses resulting from the heat expansion in the vane root region, which stresses can lead to material defects, the guide vanes and the intermediate pieces are inserted in the casing with play. When the vanes are installed in the casing, paper interlays are placed between the vane roots in order to distribute the play evenly onto the periphery. Some intermediate pieces are fixed by means of underlays inserted beneath the intermediate pieces. During running of the compressor, the paper interlays burn. If the gas turbine aggregate is switched off and re-started, the fixing of the intermediate pieces can be loosened by vibrations. The guide vanes can consequently slide together in the cooled state.
The vanes are respectively installed in the axially divided casing at the site of erection of the compressor. Conditioned by the inaccuracy ensuing from the summation of the production tolerances of the individual elements and as a result of the play distribution with paper interlays, the elements which are situated at the partition plane of the casing can only be precisely machined at the site of erection. To this end, the guide vanes are installed in the casing with paper interlays, the protruding, close-off elements situated at the partition plane are milled over, and holes for fastening the close-off elements are drilled. In order to remove chips and dirt, all elements have to be removed again. Following cleaning, the elements are reinstalled in just the same way as in the first installation step. This means a high labor expenditure and, therefore, high costs.